1. Field
The following description relates to a broadcasting service system, and more particularly, to a method of obtaining service information to receive a broadcasting service in a user equipment (UE) and service information announcement methods performable in a service center in charge of multimedia broadcast/multicast service (MBMS) control and a server interoperable with the service center.
2. Description of the Related Art
From the viewpoint of communication and broadcasting convergence, service techniques of transferring multimedia content through a mobile communication network by broadcasting or multicasting have been introduced and are already being implemented. As an example of the service techniques, an evolved multimedia broadcast/multicast service (EMBMS) is provided in a third generation partnership project (3GPP) mobile communication network. The EMBMS transmits a multimedia content packet obtained from a content provider (CP) or multicast broadcast (MB) source server, which is a data source, to a plurality of UEs through a mobile communication network by broadcasting or multicasting. In other words, an EMBMS service system transmits the corresponding content only once such that a plurality of users can simultaneously receive the content.
In such a point-to-multipoint service, resources of a mobile communication network may be saved because EMBMS content is transmitted once from a CP/MB source server to a broadcast/multicast channel shared by a plurality of UEs. In the point-to-multipoint service, content providers interoperate with an evolved broadcast multicast service center (eBM-SC) managing and controlling an EMBMS, and the eBM-SC interoperates with a packet data node (PDN) gateway (PGW) operating for a packet data service in a mobile communication network and multimedia broadcast multicast service 2 (MBMS2), such that multimedia content is transmitted to a terminal through the mobile communication network.
The EMBMS is frequently used in wireless communication network systems such as wideband code division multiple access (WCDMA) networks, and European mobile phone (e.g., a global system for mobile communication (GSM) phone) networks. In the EMBMS, a BM-SC, a network element defined for EMBMS management, simultaneously transfers content to several terminals using a packet core network for a conventional packet service and a bearer provided by an evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (EUTRAN).
To provide multimedia broadcasting service through a mobile communication network, it must be known what service a terminal can use in a region. Thus, an eBM-SC must announce service information in order to inform a mobile terminal of an available broadcast/multicast service list and various information required to receive a related service. Using the announced information, the mobile terminal sets up its environment and provides the service list to a user, thereby enabling the user to select a desired specific EMBMS.
The announcement of service information may be performed in a mobile communication network using an EMBMS broadcast or multicast bearer, a service framework provided in a conventional mobile communication network, such as a multimedia messaging service (MMS), short message service (SMS), call broadcast service (CBS), and wireless application protocol (WAP), or a service method generally used to transfer documents between a web server and a client browser in a wired Internet network. While it is specified in the standards that these techniques can be applied to service information announcement, it is not specified in the standards how the techniques are applied.
When a user wants to use a specific service through a terminal in a mobile communication network or the terminal is moved to a new area, the terminal must obtain a list of services that can be provided in the area and information about the services from a service providing system and provide the list and information through a user interface (UI) such that a user can select one of the services.
In the above-mentioned methods other than the WAP technique and the method using a web server, service providing systems unilaterally transfer service information. In such a method in which a service providing system unilaterally transfers service information, the system must announce service information constantly, at a specific event, or at specific periods such that mobile terminals can obtain the latest service information. Thus, unless service information is constantly transmitted, the mobile terminals cannot obtain service information about the corresponding service area before a change is made in the service. When service information is frequently announced to solve this problem, a large amount of wireless resources are occupied. Also, the larger the amount of service information, the higher wireless resource occupancy is.
On the other hand, in the WAP technique or the method using a web server, a terminal requests service information from a system and obtains it. When the WAP technique or the method using a web server is applied, the terminal cannot know that or when service information has been changed, and thus must request service information in relatively short time intervals to obtain the latest service information. In this case, the power consumption of the terminal increases. Also, since all terminals must receive unicasted service information, the service providing system must respond to the respective requests of the terminals. Thus, the processing load of the system increases, and wireless resources are wasted.